The campaign for Democratic candidate Mike Espy, a former U.S. congressman and U.S. agriculture secretary, has been relatively quiet, likely keeping powder dry as the two Republicans spar. The three, plus lesser known Democrat Tobey Bartee of Gautier, face off Nov. 6 in a special general election to fill out the last two years of Cochran's term. Gov. Phil Bryant appointed Hyde-Smith in April to temporarily fill the post.

A Hyde-Smith spokeswoman said the appointed senator's fundraising performance shows "outpouring of support from so many Mississippians and conservatives across America." The total was released in advance of the July 15 deadline to file full campaign finance reports.

Raising substantial campaign funds is reportedly one of the benchmarks the Trump White House set for Hyde-Smith as prerequisite for potential endorsement by the president.

McDaniel on Thursday said his fundraising is going well but, "We will never out-raise Mitch McConnell and the lobbyists of the swamp."

McDaniel at his news conference said signing the lengthy contract with Mississippians is about accountability and showing he's different from his opponents.

McDaniel pledges in the contract that he will support spending reform including Sen. Rand Paul's "Penny Plan" and will never vote for any budget that increases federal debt. He vowed to support tax cuts and repeals, regulatory and judicial reform and the Second Amendment. He also vowed to support increased defense spending.

On Social Security, McDaniel said: "I will never support raising taxes, borrowing more money or reducing benefits. That leaves one option, cut spending elsewhere to boost Social Security."